Nick Watney has a one-shot lead after the opening round of the World Challenge in Thousand Oaks, California.
The American was the only player to avoid a bogey at the Sherwood Country Club on Thursday as a 67 left him on five-under-par.
Fellow countrymen Keegan Bradley and Jim Furyk ended the day on three-under with Northern Ireland's Graeme McDowell.
Tiger Woods and Webb Simpson are a shot further back, while Bubba Watson is one of three players on one-under.
England's Ian Poulter endured a frustrating first day out on the course as a double bogey on the 14th saw him finish with a score of one-over.